Remove string attribute from views

issue2350

view/price_list_form.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0"?>
 <!-- This file is part of Tryton.  The COPYRIGHT file at the top level of
 this repository contains the full copyright notices and license terms. -->
-<form string="Price List">
+<form>
     <label name="name"/>
     <field name="name"/>
     <label name="company"/>

view/price_list_line_form.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0"?>
 <!-- This file is part of Tryton.  The COPYRIGHT file at the top level of
 this repository contains the full copyright notices and license terms. -->
-<form string="Price List Line">
+<form>
     <label name="price_list"/>
     <field name="price_list"/>
     <newline/>

view/price_list_line_tree.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0"?>
 <!-- This file is part of Tryton.  The COPYRIGHT file at the top level of
 this repository contains the full copyright notices and license terms. -->
-<tree string="Price List Lines">
+<tree>
     <field name="price_list"/>
     <field name="sequence"/>
     <field name="product"/>

view/price_list_line_tree_sequence.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0"?>
 <!-- This file is part of Tryton.  The COPYRIGHT file at the top level of
 this repository contains the full copyright notices and license terms. -->
-<tree string="Price List Lines" sequence="sequence">
+<tree sequence="sequence">
     <field name="product"/>
     <field name="quantity"/>
     <field name="formula"/>

view/price_list_tree.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0"?>
 <!-- This file is part of Tryton.  The COPYRIGHT file at the top level of
 this repository contains the full copyright notices and license terms. -->
-<tree string="Price Lists">
+<tree>
     <field name="name"/>
     <field name="tax_included"/>
 </tree>